Note: Descriptions are shown in the official language in which they were submitted.
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Use of distillable volatile salt for the pretreatment of biomass
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Patent Application
Ser. No.
62/978,771, filed February 19, 2020, which is incorporated by reference in its
entirety.
STATEMENT OF GOVERNMENTAL SUPPORT
[0002] The invention was made with government support under Contract Nos. DE-
ACO2-
05CH11231 awarded by the U.S. Department of Energy. The government has certain
rights
in the invention.
FIELD OF THE INVENTION
[0003] The present invention is in the field of using distillable volatile
salt for biomass
pretreatment.
BACKGROUND OF THE INVENTION
[0004] Biofuels and bioproducts derived from sustainable feedstocks are
considered a
potential solution to address the challenges associated with human population
growth. For
efficient biofuel production, the biochemical conversion of lignocellulosic
biomass has been
frequently discussed in terms of process optimization as well as the reaction
mechanism of
various thermochemical processing (e.g., pretreatment) and biochemical
conversion (e.g.,
enzymatic hydrolysis and fermentation). Current challenges to the realization
of an affordable
and scalable biomass conversion technology are those associated with
complicated process
designs, difficulties associated with efficient solvent recycle, and water
consumption.
SUMMARY OF THE INVENTION
[0005] The present invention provides for using a distillable volatile salt,
or a mixture
thereof, for the pretreatment of biomass. In some embodiments, the distillable
volatile salt is
an ionic liquid or a deep eutectic solvent, or a mixture thereof
[0006] The present invention provides for a method to produce a sugar from a
biomass, the
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method comprising: (a) providing a first mixture comprising a solubilized
biomass and a
distillable acid-base conjugate salt (DABCS) or deep eutectic solvent (DES),
wherein (i) the
DABCS is a protic ionic liquid (PIL) or a protic salt comprising a DABCS
cation and a
DABCS anion, and (ii) the DES is any combination of Lewis or Bronsted acid and
base
comprising any anionic and/or cationic species that have sufficient vapor
pressure so that it
can be readily distilled; (b) distilling at least part of the DABCS from the
first mixture in
order to separate the at least part of the DABCS from the first mixture; (c)
optionally
introducing an enzyme and/or a microbe to the first mixture such that the
enzyme and/or
microbe produce a sugar from the solubilized biomass; and, (d) optionally the
sugar is
separated from the first mixture.
[0007] In some embodiments, the method further comprises (e) introducing at
least part of
the DABCS separated in the (b) distilling step to the first mixture in step
(a).
[0008] In some embodiments, the method further comprises (0 introducing more
biomass to
the first mixture in step (a).
[0009] The present invention provides for a first mixture comprising a biomass
and a
distillable acid-base conjugate salt (DABCS) comprising a DABCS cation, and a
DABCS
anion.
[0010] The present invention provides for a system comprising a reactor
vessel, a condenser,
a collection chamber, one or more cold traps, and low pressure source; wherein
the reactor
vessel is in fluid communication with a condenser, wherein the condenser is in
fluid
communication with (i) the collection chamber and (ii) the low pressure source
via the one or
more cold traps. In some embodiments, the reactor vessel comprises a double
wall and/or a
mixer or propeller. In some embodiments, the condenser has a temperature of
about 0 C, -5
C, -10 C, -15 C, -20 C, -25 C, -30 C, -35 C, -40 C, -45 C, or -50 C.
In some
embodiments, each cold trap has a temperature lower than the temperature of
the condenser,
such as about -60 C, -65 C, -70 C, -75 C, -80 C, -85 C, or -90 C. In
some
embodiments, the low pressure source is a vacuum pump, for example the vacuum
pump is
creating a pressure of about 1 m ton.
[0011] In some embodiments, the reaction vessel contains the first mixture of
the present
invention. In some embodiments, the first mixture has a solid loading of about
5%, 10%,
15%, or 20%. In some embodiments, the first mixture is heated to a temperature
of about 100
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C, 110 C, 120 C, 130 C, 140 C, 150 C, or 160 C, or any temperature
between any two
of the preceding temperatures. In some embodiments, the first mixture is
incubated for a first
time for about 1 h, 2 h, 3 h, 4 h, or 5 h.
[0012] In some embodiments, after the first incubation, the first mixture is
subjected to a
distilling step, wherein the first mixture is heated to a temperature of about
100 C, 110 C,
120 C, 130 C, 140 C, 150 C, or 160 C, or any temperature between any two
of the
preceding temperatures, and a low pressure (produced by the low pressure
source) applied to
the reaction vessel. Distillable IL/DES/solvent (from the liquid phase in the
first mixture) is
converted into the gaseous phase and is conveyed to the condenser, where it
converts back
into the liquid phase and is collected in the collection chamber.
[0013] In some embodiments, after the distilling step, the temperature is
lowered to about 25
C, 30 C, 35 C, 37 C, or 40 C, a suitable enzyme or microbe, or mixture
thereof, is added
to the first mixture, and incubated for a second time for about 24 h, 48 h, 72
h, 96 h, or 120 h.
The second incubation results in the production of one or more sugar monomers,
such as
hexoses and/or pentoses.
[0014] The present invention provides for compositions and methods described
herein.
[0015] In some embodiments, the compositions and methods further comprise
steps, features,
and/or elements described in U.S. Patent Application Ser. No. 16/737,724,
hereby
incorporated by reference in its entirety.
[0016] In some embodiments, the method further comprises one or more of the
following: (a)
introducing a biomass and a deep eutectic solvent (DES), or mixture thereof,
into a vessel to
form a one-pot composition, wherein the DES, or mixture thereof, solubilizes
the biomass;
(b) introducing an enzyme and/or a microbe to the one-pot composition such
that the enzyme
and/or microbe produce a biofuel and/or chemical compound from the solubilized
biomass;
and, (c) optionally separating the biofuel and/or chemical compound from the
one-pot
composition. In some embodiments, the introducing steps (a) and (b), and
optionally the
separating step (c), are continuous.
[0017] In some embodiments, the method, or one-pot method, does not require
any solid-
liquid separation step. In some embodiments, the one-pot method does not
require adjustment
of the pH level in the one-pot composition. In some embodiments, the one-pot
method does
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not require any dilution, or addition of water or medium, after pretreatment
and/or before
saccharification and fermentation. In some embodiments, the reaction of the
enzyme and the
growth of the microbe occur in the same one-pot composition. In some
embodiments, the
DES, or mixture thereof, is renewable as it can be continuous in use. In some
embodiments,
the one-pot method can produce a yield of sugar that is equal to or more than
about 50%,
55%, 60%, 65%, 70%, 75%, or 80%, or any other value described herein.
[0018] In some embodiments, the one-pot biomass pretreatment,
saccharification, and
fermentation with bio-compatible deep eutectic solvents (DESs). The used bio-
compatible
DESs are tested for microbial, such as yeast, compatibility and toxicity. The
pretreatment
efficacy of the selected DESs are tested. The uses of the DESs for biomass
processing
eliminates the need to remove any solvent after biomass pretreatment, thus
making the one-
pot approach possible.
[0019] In some embodiments, using bio-compatible DESs enables a one-pot
biomass
conversion which eliminates the needs of mass transfer between reactors and
the separation
of solid and liquid. In some embodiments, the method does not require
recycling any catalyst
and/or enzyme. In some embodiments, the method requires less water usage than
current
biomass pretreatment. The method can produce fuels/chemicals at a higher titer
and/or yield
in a single vessel without any need for intermediate units of mass transfer
and/or solid/liquid
separation.
[0020] This invention provides for the use of volatile protic salts (such as
ionic liquids) and
deep eutectic solvents to develop an integrated biomass pretreatment approach
that combines
effective IL-based pretreatment with a simplistic and energy efficient IL
recovery/recycling
method. This novel method enables the cost-effective production of IL-based
fermentable
sugars¨a major hurdle for producing commercially viable bioenergy from waste
biomass.
By integrating a vacuum distillation for the salt recovery/recycling into the
overall
pretreatment process, the development of the most favorable process
configuration is
facilitated that maximizes both IL recovery, along with, pretreatment
effectiveness (such as
sugar yield and/or lignin yield). Subsequently different salts can be screened
to identify key
structural features that enhance the overall process economics.
[0021] The utilization of protic ionic salts, such as ionic liquids (Its) and
deep eutectic
solvents (DESs), as biomass pretreatment solvents is one of the most effective
methods for
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producing high yields of fermentable sugars for bioenergy production. However,
the cost of
IL utilization is a significant problem that must be addressed before an
affordable IL/DES-
based process is commercially viable. Therefore, this invention describes a
combined method
for performing biomass pretreatment that involves utilizing protic salts that
are relatively
cheap, effective at deconstructing biomass and most importantly¨readily
recyclable. In some
embodiments, the method comprises an integrated/one-pot approach for carrying
out
pretreatment, IL recovery/recycle, enzymatic hydrolyses (such as for sugar
release) and
fermentation sequentially to minimize the need for tedious downstream
separation and to
maximize biofuel/bioproduct yield.
[0022] For this process, a distillable acid-base conjugate salt can be
utilized, such as a protic
ionic liquid (PM), as well as DESs that can be effortlessly recycled with
little energy input to
enable their easy recovery. Effective PILs for this process should be
recovered at least equal
to more than about 85% yield by distilling over vacuum at T< about 160 C,
while releasing
at least about 85% fermentable sugars. These PILs (such as
hydroxyethylammonium acetate -
[Eth][0Ac]) are demonstrated to be effective for biomass pretreatment and are
also relatively
cheap due to their ease of synthesis. To develop this process, it was
necessary to develop the
most favorable process configuration to maximize both IL recovery, along with,
pretreatment
effectiveness (such as sugar yield and/or lignin yield). Subsequently several
ILs can be
screened to identify analogous ILs with similar cations/anions in order to
improve the overall
process economics. Suitable salts for this process include combinations of
organic
ammonium-based cations (such as ammonium, hydroxyalkylammonium,
dimethylalkylammonium) with organic carboxylic acid-based anions (such as
acetic acid
derivatives (C1-C8), lactic acid, glycolic acid, as well as, DESs such as
ammonium
acetate/lactic acid.
[0023] Preliminary results show that the PIL¨[Eth][0Ac] can be recovered at a
rate of [-85-
98] % in a one-pot setup depending on the solids loading of the biomass.
Additional work
needs to be carried out to optimize the process configuration for high
recovery yield, as well
as, to discover other PILs and/or DESs that may have improved pretreatment
efficiency
and/or recovery rates.
[0024] The invention outlined here provides numerous advantages including one
or more of
the following: (1) Developing cheaper solvents for biomass pretreatment, (2)
Effective at
pretreatment (via lignin extraction and reducing biomass recalcitrance), (3)
facile recycling
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and recover of ILs and DESs via vacuum distillation, and (4) Integrated
approach for the
conversion of biomass to biobased fuels.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] The foregoing aspects and others will be readily appreciated by the
skilled artisan
from the following description of illustrative embodiments when read in
conjunction with the
accompanying drawings.
[0026] Figure 1. An embodiment for the recovery of distillable IL/solvent.
[0027] Figure 2. A Piping and instrumentation Diagram (P&ID) of an embodiment
of a
method for the recovery of distillable IL/solvent used in a biomass
pretreatment system.
[0028] Figure 3. A P&ID of an embodiment of a method for the recovery of
distillable
IL/solvent used in a biomass pretreatment system.
[0029] Figure 4. Concentration of pretreating solvent in the solids after
pretreatment..
[0030] Figure 5. Analysis of sugars and acids in solids after distillation.
"HMF" refers to
hydroxymethylfurfural.
[0031] Figure 6. Analysis of aromatics in solids after distillation. "4HBA"
refers to 4-
hydroxybenzoic acid.
[0032] Figure 7. Sugar release after pretreatment, distillation and
saccharification.
DETAILED DESCRIPTION OF THE INVENTION
[0033] Before the invention is described in detail, it is to be understood
that, unless otherwise
indicated, this invention is not limited to particular sequences, expression
vectors, enzymes,
host microorganisms, or processes, as such may vary. It is also to be
understood that the
terminology used herein is for purposes of describing particular embodiments
only, and is not
intended to be limiting.
[0034] In this specification and in the claims that follow, reference will be
made to a number
of terms that shall be defined to have the following meanings:
[0035] The terms "optional" or "optionally" as used herein mean that the
subsequently
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described feature or structure may or may not be present, or that the
subsequently described
event or circumstance may or may not occur, and that the description includes
instances
where a particular feature or structure is present and instances where the
feature or structure
is absent, or instances where the event or circumstance occurs and instances
where it does
not.
[0036] The term "about" when applied to a value, describes a value that
includes up to 10%
more than the value described, and up to 10% less than the value described.
[0037] Where a range of values is provided, it is understood that each
intervening value, to
the tenth of the unit of the lower limit unless the context clearly dictates
otherwise, between
the upper and lower limits of that range is also specifically disclosed. Each
smaller range
between any stated value or intervening value in a stated range and any other
stated or
intervening value in that stated range is encompassed within the invention.
The upper and
lower limits of these smaller ranges may independently be included or excluded
in the range,
and each range where either, neither or both limits are included in the
smaller ranges is also
encompassed within the invention, subject to any specifically excluded limit
in the stated
range. Where the stated range includes one or both of the limits, ranges
excluding either or
both of those included limits are also included in the invention.
[0038] DESs are systems formed from a eutectic mixture of Lewis or Bronsted
acids and
bases which can contain a variety of anionic and/or cationic species. DESs can
form a
eutectic point in a two-component phase system. DESs are formed by
complexation of
quaternary ammonium salts (such as, choline chloride) with hydrogen bond
donors (HBD)
such as amines, amides, alcohols, or carboxylic acids. The interaction of the
HBD with the
quaternary salt reduces the anion-cation electrostatic force, thus decreasing
the melting point
of the mixture. DESs share many features of conventional ionic liquid (IL),
and promising
applications would be in biomass processing, electrochemistry, and the like.
Any Lewis or
Bronsted acid and base combination can be used in the invention as long as the
combination
is distillable.
[0039] Typically, DES is prepared using an alcohol (such as glycerol or
ethylene glycol),
amines (such as urea), and an acid (such as oxalic acid or lactic acid). The
present invention
can use renewable DESs with lignin-derived phenols as HBDs. Both phenolic
monomers and
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phenol mixture readily form DES upon heating at 100 C with specific molar
ratio with
choline chloride. This class of DES does not require a multistep synthesis.
The novel DES is
synthesized from lignin which is a renewable source.
[0040] Both monomeric phenols and phenol mixture can be used to prepare DES.
DES is
capable of dissolving biomass or lignin, and can be utilized in biomass
pretreatment and other
applications. Using DES produced from biomass could lower the cost of biomass
processing
and enable greener routes for a variety of industrially relevant processes.
[0041] The DES, or mixture thereof, is bio-compatible: meaning the DES, or
mixture thereof,
does not reduce or does not significantly reduce the enzymatic activity of the
enzyme, and/or
is not toxic, and/or does not reduce or significantly reduce, the growth of
the microbe. A
"significant" reduction is a reduction to 70, 80, 90, or 95% or less of the
enzyme's enzymatic
activity and/or the microbe's growth (or doubling time), if the DES, or
mixture thereof, was
not present.
[0042] In some embodiments, the DES, or mixture thereof, comprises a
quaternary
ammonium salt and/or glycerol. In some embodiments, the DES, or mixture
thereof,
comprises a quaternary ammonium salt and/or glycerol. In some embodiments, the
quaternary ammonium salt and/or glycerol have a molar ratio of about 1:1 to
about 1:3. In
some embodiments, the quaternary ammonium salt and/or glycerol have a molar
ratio of
about 1:1.5 to about 1:2.5. In some embodiments, the quaternary ammonium salt
and/or
glycerol have a molar ratio of about 1:1.8 or 1:1.9 to about 1:2.1 or 1:2.2.
In some
embodiments, the quaternary ammonium salt and/or glycerol have a molar ratio
of about 1:2.
In some embodiments, the quaternary ammonium salt is a choline halide, such
choline
chloride.
[0043] In some embodiments, the DABCS or DES is distillable if the DABCS or
DES can be
recovered at least equal to or more than about 50%, 55%, 60%, 65%, 70%, 75%,
80%, or
85% yield by distilling over vacuum at a temperature at about 100 C, 110 C,
120 C, 130
C, 140 C, 150 C, or 160 C, or any temperature between any two of the
preceding
temperatures. In some embodiments, the method results in the releasing of at
least equal to or
more than about 60%, 65%, 70%, 75%, 80%, or 85% fermentable sugars.
[0044] Suitable protic ionic liquids (PILs) include fused salts with a melting
point less than
100 C with salts that have higher melting points referred to as molten salts.
Suitable PPILs
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are disclosed in Greaves et al. "Protic Ionic Liquids: Properties and
Applications" Chem. Rev.
108(1):206-237 (2008). PILs can be prepared by the neutralization reaction of
certain
Bronsted acids and Bronsted bases (generally from primary, secondary or
tertiary amines,
which are alkaline) and the fundamental feature of these kinds of ILs is that
their cations have
at least one available proton to form hydrogen bond with anions. In some
embodiments, the
protic ionic liquids (PILs) are formed from the combination of organic
ammonium-based
cations and organic carboxylic acid-based anions. PILs are acid-base conjugate
ILs that can
be synthesized via the direct addition of their acid and base precursors. In
some
embodiments, the Pit is a hydroxyalkylammonium carboxylate. In some
embodiments, the
hydroxyalkylammonium comprises a straight or branched Cl, C2, C3, C4, C5, C6,
C7, C8,
C9, or C10 chain. In some embodiments, the carboxylate comprises a straight or
branched
Cl, C2, C3, C4, C5, C6, C7, C8, C9, or C10 chain. In some embodiments, the
carboxylate is
substituted with one or more hydroxyl groups. In some embodiments, the Pit is
a
hydroxyethyl ammonium acetate.
[0045] In some embodiments, the protic ionic liquid (Pit) is disclosed by U.S.
Patent
Application Publication No. 2004/0097755, hereby incorporated by reference.
[0046] Suitable salts for the method include combinations of organic ammonium-
based
cations (such as ammonium, hydroxyalkylammonium, or dimethylalkylammonium)
with
organic carboxylic acid-based anions (such as acetic acid derivatives (C1-C8),
lactic acid,
glycolic acid, and DESs such as ammonium acetate/lactic acid.
[0047] Suitable distillable ionic liquids are disclosed in Chen et al.
"Distillable Ionic Liquids:
reversible Amide 0 Alkylation", Angewandte Comm. 52:13392-13396 (2013), King
et al.
"Distillable Acid-Base Conjugate Ionic Liquids for Cellulose Dissolution and
Processing",
Angewandte Comm. 50:6301-6305 (2011), and Vijayaraghavan et al. "CO2-based
Alkyl
Carbamate Ionic Liquids as Distillable Extraction Solvents", ACS Sustainable
Chem. Engin.
2:31724-1728 (2014), all of which are hereby incorporated by reference.
[0048] Suitable distillable PIL are disclosed in Idris et al. "Distillable
Protic Ionic Liquids for
Keratin Dissolution and Recovery", ACS Sustainable Chem. Engin. 2:1888-1894
(2014) and
Sun et al. "One-pot integrated biofuel production using low-cost biocompatible
protic ionic
liquids", Green Chem. 19:3152-3163 (2017), all of which are hereby
incorporated by
reference.
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[0049] In some embodiments, the method further comprises heating the one-pot
composition,
optionally also comprising the enzyme and/or microbe, to a temperature that is
equal to,
about, or near the optimum temperature for the enzymatic activity of the
enzyme and/or
growth of the microbe. In some embodiments, the enzyme is a genetically
modified host cell
capable of converting the cellulose in the biomass into a sugar. In some
embodiments, there
is a plurality of enzymes. In some embodiments, the microbe is a genetically
modified host
cell capable of converting a sugar produced from the biomass into a biofuel
and/or chemical
compound. In some embodiments, there is a plurality of microbes. In some
embodiments, the
introducing steps (a) and (b) together produce a sugar and a lignin from the
biomass. The
lignin can further be processed to produce a DES. The sugar is used for growth
by the
microbe.
[0050] In some embodiments, the solubilizing is full, near full (such as at
least about 70, 80,
or 90%), or partial (such as at least about 10, 20, 30, 40, 50, or 60%). In
some embodiments,
the one-pot composition is a slurry. When the steps (a) to (c) are continuous,
the one-pot
composition is in a steady state.
[0051] In some embodiments, the DES can be one taught in WO 2018/204424 (Seema
Singh
et al.), which is hereby incorporated in its entirety by reference.
[0052] In some embodiments, all or some of the one-pot composition is further
pretreated as
follows: the method further comprising: (d) optionally separating the sugar
and the lignin in
the one-pot composition, (e) depolymerizing and/or converting the lignin into
one or more
lignin derived monomeric phenol, or a mixture thereof, (f) providing the one
or more lignin
derived monomeric phenol, or a mixture thereof, in a solution, (g) introducing
one or more
quaternary ammonium salts, or a mixture thereof, to the solution, (h) heating
the solution,
such that steps (g) and (h) together result in the synthesis of a DES, (i)
optionally forming a
DES system from the DES synthesized in step (h), and (j) optionally repeating
steps (d) to (i)
using the DES system formed in step (i) in the introducing step (a).
[0053] In some embodiments, the heating step (h) comprises increasing the
temperature of
the solution to a value within a range of about 75 C to about 125 C. In some
embodiments,
the heating step (h) comprises increasing the temperature of the solution to a
value within a
range of about 80 C to about 120 C. In some embodiments, the heating step
(h) comprises
increasing the temperature of the solution to a value within a range of about
90 C to about
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110 C. In some embodiments, the heating step (h) comprises increasing the
temperature of
the solution to about 100 C.
[0054] In some embodiments, the enzyme is a cellulase. In some embodiments,
the enzyme is
a cellulase. In some embodiments, the enzyme is thermophilic or
hyperthermophilic. In some
embodiments, the enzyme is any enzyme taught in U.S. Patent Nos. 9,322,042;
9,376,728;
9,624,482; 9,725,749; 9,803,182; and 9,862,982; and PCT International Patent
Application
Nos. PCT/US2015/000320, PCT/US2016/063198, PCT/US2017/036438,
PCT/US2010/032320, and PCT/US2012/036007 (all of which are incorporated in
their
entireties by reference).
[0055] In some embodiments, the microbe is any prokaryotic or eukaryotic cell,
with any
genetic modifications, taught in U.S. Patent Nos. 7,985,567; 8,420,833;
8,852,902;
9,109,175; 9,200,298; 9,334,514; 9,376,691; 9,382,553; 9,631,210; 9,951,345;
and
10,167,488; and PCT International Patent Application Nos. PCT/U514/48293,
PCT/US2018/049609, PCT/US2017/036168, PCT/US2018/029668, PCT/U52008/068833,
PCT/U52008/068756, PCT/US2008/068831, PCT/US2009/042132, PCT/US2010/033299,
PCT/U52011/053787, PCT/U52011/058660, PCT/US2011/059784, PCT/U52011/061900,
PCT/US2012/031025, and PCT/U52013/074214 (all of which are incorporated in
their
entireties by reference).
[0056] In some embodiments, the biofuel produced is ethanol, or any other
organic molecule,
described produced in a cell taught in U.S. Patent Nos. 7,985,567; 8,420,833;
8,852,902;
9,109,175; 9,200,298; 9,334,514; 9,376,691; 9,382,553; 9,631,210; 9,951,345;
and
10,167,488; and PCT International Patent Application Nos. PCT/U514/48293,
PCT/US2018/049609, PCT/US2017/036168, PCT/US2018/029668, PCT/U52008/068833,
PCT/U52008/068756, PCT/US2008/068831, PCT/US2009/042132, PCT/US2010/033299,
PCT/U52011/053787, PCT/U52011/058660, PCT/US2011/059784, PCT/U52011/061900,
PCT/US2012/031025, and PCT/U52013/074214 (all of which are incorporated in
their
entireties by reference).
[0057] Deep eutectic solvents (DESs) share the promising solvent properties of
ionic liquids.
They show low volatility, wide liquid range, water-compatibility, non-
flammability, non-
toxicity, biocompatibility and biodegradability. Furthermore, DES can be
easily prepared
from readily available materials at high purities and low cost compared to
ILs. Lignin is the
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second most abundant naturally occurring polymer next to cellulose, which
represents a
significant component of carbon on earth. Large amount of technical lignins
such as Kraft
lignin and lignosulfonate is produced as by-products in the pulp and paper
industries. It is
also expected that more lignin will become available in coming years as the
production
capability of second generation of biofuels increases. As a renewable and
resource, lignin and
lignin derived products (phenolic) are an important material. DESs with lignin-
derived
phenolic compounds either as a single monomer or phenolic mixture can be used
in the
present invention.
[0058] The one-pot biomass pretreatment, saccharification, and fermentation
with bio-
compatible deep eutectic solvents (DESs). The used bio-compatible DESs are
tested for
microbial, such as yeast, compatibility and toxicity. The pretreatment
efficacy of the selected
DESs are tested. The uses of the DESs for biomass processing eliminates the
need to remove
any solvent after biomass pretreatment, thus making the one-pot approach
possible.
[0059] In some embodiments, the biomass is a lignocellulosic biomass. In some
embodiments, the vessel is made of a material that is inert, such as stainless
steel or glass,
which does not react or interfere with the reactions in the one-pot
composition.
[0060] In some embodiments, the pretreatment comprises about 0.5 g of biomass
(such as
corn stover) mixed thoroughly with about 4.5 g DES (such as choline chloride
and glycerol)
in a suitable inert vessel, such as a glass vessel, followed by heating up to
about 180 C and
the temperature is maintained for a suitable period of time, such as about 2
hours. After
pretreatment, the resulting slurry is cooled to below about 50 C and is
immediately ready for
the following saccharification and microbial conversion. The saccharification
is carried out
with a suitable enzyme, such as a commercial enzyme mixture (for example,
CTec2 and
HTec2 from Novozymes A/S (Bagsvxrd, Denmark), at about 50 C and about pH 5 at
about
48 rpm in an incubator with shaking function. After a suitable period of time,
such as about
48 hours, of saccharification, the generated sugar stream is then immediately
ready for
microbial conversion. For example, a wild-type yeast, such as Saccharomyces
cerevisiae, is
inoculated at temperature (about 30 C to about 37 C) for anaerobic ethanol
fermentation.
[0061] In some embodiments, using bio-compatible DESs enables a one-pot
biomass
conversion which eliminates the needs of mass transfer between reactors and
the separation
of solid and liquid. In some embodiments, the method does not require
recycling any catalyst
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and/or enzyme. In some embodiments, the method requires less water usage than
current
biomass pretreatment. The method can produce fuels/chemicals at a higher titer
and/or yield
in a single vessel without any need for intermediate units of mass transfer
and/or solid/liquid
separation.
[0062] In some embodiments, ethanolaminium acetate [Eth][0Ac] is a PIL that is
recoverable/recyclable via distillation.
[0063] In some embodiments, the acid¨base conjugate ILs (such as,.1,1,3,3-
tetramethylguanidinium propionate ([TMGH][CO2Et])64 and 1,5-
diazabicyclo[4.3.0]non-5-
enium propionate ([DBNH][CO2Et])102) are synthesized for efficient biomass
treatment.
Their distillable characteristic is attributed to the higher acidity of the
cations, allowing for
the dissociation of ILs to the neutral acid and base IL precursors at elevated
temperatures. For
example, when being heated to a temperature about 100-200 C under reduced
pressure (1
mmHg), the [TMGH][CO2Et] is dissociated into the 1,1,3,3-tetramethylguanidine
(TMG)
and carboxylate (HCO2Et).
[0064] For the distillable ILs-protic ILs an equilibrium exists between the IL
precursors and
IL:
B = +A ¨ H = [-13 ¨JI 1! A- 1,,i1
=(,`
4 ¨ H()
The equilibrium can be pushed to either side based on reaction coordinates,
such as pressure,
temperature, or the like. Figure 1 shows an embodiment for the recovery of
distillable
IL/solvent.
[0065] Figure 2 shows an embodiment of a method/system for the recovery of
distillable
IL/solvent used in a biomass pretreatment system. Figure 3 shows another
embodiment of a
method/system for the recovery of distillable IL/solvent used in a biomass
pretreatment
system.
DEEP EUTECTIC SOLVENT (DES)
[0066] DESs are systems formed from a eutectic mixture of Lewis or Bronsted
acids and
bases which can contain a variety of anionic and/or cationic species. DESs can
form a
eutectic point in a two-component phase system. DESs are formed by
complexation of
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quaternary ammonium salts (such as, choline chloride) with hydrogen bond
donors (HBD)
such as amines, amides, alcohols, or carboxylic acids. The interaction of the
HBD with the
quaternary salt reduces the anion-cation electrostatic force, thus decreasing
the melting point
of the mixture. DESs share many features of conventional ionic liquid (IL),
and promising
applications would be in biomass processing, electrochemistry, and the like.
In some
embodiments, the DES is any combination of Lewis or Bronsted acid and base. In
some
embodiments, the Lewis or Bronsted acid and base combination used is
distillable.
[0067] In some embodiments, DES is prepared using an alcohol (such as glycerol
or ethylene
glycol), amines (such as urea), and an acid (such as oxalic acid or lactic
acid). The present
invention can use renewable DESs with lignin-derived phenols as HBDs. Both
phenolic
monomers and phenol mixture readily form DES upon heating at 100 C with
specific molar
ratio with choline chloride. This class of DES does not require a multistep
synthesis. The
DES is synthesized from lignin which is a renewable source.
[0068] Both monomeric phenols and phenol mixture can be used to prepare DES.
DES is
capable of dissolving biomass or lignin, and can be utilized in biomass
pretreatment and other
applications. Using DES produced from biomass could lower the cost of biomass
processing
and enable greener routes for a variety of industrially relevant processes.
[0069] The DES, or mixture thereof, is bio-compatible: meaning the DES, or
mixture thereof,
does not reduce or does not significantly reduce the enzymatic activity of the
enzyme, and/or
is not toxic, and/or does not reduce or significantly reduce, the growth of
the microbe. A
"significant" reduction is a reduction to 70, 80, 90, or 95% or less of the
enzyme's enzymatic
activity and/or the microbe's growth (or doubling time), if the DES, or
mixture thereof, was
not present.
[0070] In some embodiments, the DES, or mixture thereof, comprises a
quaternary
ammonium salt and/or glycerol. In some embodiments, the DES, or mixture
thereof,
comprises a quaternary ammonium salt and/or glycerol. In some embodiments, the
quaternary ammonium salt and/or glycerol have a molar ratio of about 1:1 to
about 1:3. In
some embodiments, the quaternary ammonium salt and/or glycerol have a molar
ratio of
about 1:1.5 to about 1:2.5. In some embodiments, the quaternary ammonium salt
and/or
glycerol have a molar ratio of about 1:1.8 or 1:1.9 to about 1:2.1 or 1:2.2.
In some
embodiments, the quaternary ammonium salt and/or glycerol have a molar ratio
of about 1:2.
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In some embodiments, the quaternary ammonium salt is a choline halide, such
choline
chloride.
[0071] In some embodiments, the DES is distillable if the DES can be recovered
at least
equal to or more than about 50%, 55%, 60%, 65%, 70%, 75%, 80%, or 85% yield by
distilling over vacuum at a temperature at about 100 C, 110 C, 120 C, 130
C, 140 C, 150
C, or 160 C, or any temperature between any two of the preceding
temperatures.
[0072] In some embodiments, the DES can be one taught in WO 2018/204424 (Seema
Singh
et al.), which is hereby incorporated in its entirety by reference.
[0073] In some embodiments, the method further comprises heating the one-pot
composition,
optionally also comprising the enzyme and/or microbe, to a temperature that is
equal to,
about, or near the optimum temperature for the enzymatic activity of the
enzyme and/or
growth of the microbe. In some embodiments, the enzyme is a genetically
modified host cell
capable of converting the cellulose in the biomass into a sugar. In some
embodiments, there
is a plurality of enzymes. In some embodiments, the microbe is a genetically
modified host
cell capable of converting a sugar produced from the biomass into a biofuel
and/or chemical
compound. In some embodiments, there is a plurality of microbes. In some
embodiments, the
introducing step(s) produce a sugar and a lignin from the biomass. The lignin
can further be
processed to produce a DES. The sugar is used for growth by the microbe.
[0074] In some embodiments, the solubilizing is full, near full (such as at
least about 70, 80,
or 90%), or partial (such as at least about 10, 20, 30, 40, 50, or 60%). In
some embodiments,
the one-pot composition is a slurry. When the steps described herein are
continuous, the one-
pot composition is in a steady state.
[0075] In some embodiments, the introducing step comprises heating the mixture
comprises
increasing the temperature of the solution to a value within a range of about
75 C to about
125 C. In some embodiments, the heating step comprises increasing the
temperature of the
solution to a value within a range of about 80 C to about 120 C. In some
embodiments, the
heating step comprises increasing the temperature of the solution to a value
within a range of
about 90 C to about 110 C. In some embodiments, the heating step comprises
increasing the
temperature of the solution to about 100 C.
ENZYME
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[0076] In some embodiments, the enzyme is a cellulase. In some embodiments,
the enzyme is
thermophilic or hyperthermophilic. In some embodiments, the enzyme is any
enzyme taught
in U.S. Patent Nos. 9,322,042; 9,376,728; 9,624,482; 9,725,749; 9,803,182; and
9,862,982;
and PCT International Patent Application Nos. PCT/US2015/000320,
PCT/US2016/063198,
PCT/US2017/036438, PCT/US2010/032320, and PCT/US2012/036007 (all of which are
incorporated in their entireties by reference).
MICROBE
[0077] In some embodiments, the microbe is any prokaryotic or eukaryotic cell,
with any
genetic modifications, taught in U.S. Patent Nos. 7,985,567; 8,420,833;
8,852,902;
9,109,175; 9,200,298; 9,334,514; 9,376,691; 9,382,553; 9,631,210; 9,951,345;
and
10,167,488; and PCT International Patent Application Nos. PCT/U514/48293,
PCT/US2018/049609, PCT/US2017/036168, PCT/US2018/029668, PCT/U52008/068833,
PCT/U52008/068756, PCT/US2008/068831, PCT/US2009/042132, PCT/US2010/033299,
PCT/U52011/053787, PCT/U52011/058660, PCT/US2011/059784, PCT/U52011/061900,
PCT/US2012/031025, and PCT/U52013/074214 (all of which are incorporated in
their
entireties by reference).
[0078] Generally, although not necessarily, the microbe is a yeast or a
bacterium. In some
embodiments, the microbe is Rhodosporidium toruloides or Pseudomonas putida.
In some
embodiments, the microbe is a Gram negative bacterium. In some embodiments,
the microbe
is of the phylum Proteobactera. In some embodiments, the microbe is of the
class
Gammaproteobacteria. In some embodiments, the microbe is of the order
Enterobacteriales.
In some embodiments, the microbe is of the family Enterobacteriaceae. Examples
of suitable
bacteria include, without limitation, those species assigned to the
Escherichia, Enterobacter,
Azotobacter, Erwinia, Bacillus, Pseudomonas, Klebsielia, Proteus, Salmonella,
Serratia,
Shigella, Rhizobia, Vitreoscilla, and Paracoccus taxonomical classes. Suitable
eukaryotic
microbes include, but are not limited to, fungal cells. Suitable fungal cells
are yeast cells,
such as yeast cells of the Saccharomyces genus.
[0079] Yeasts suitable for the invention include, but are not limited to,
Yarrowia, Candida,
Bebaromyces, Saccharomyces, Schizosaccharomyces and Pichia cells. In some
embodiments, the yeast is Saccharomyces cerevisae. In some embodiments, the
yeast is a
species of Candida, including but not limited to C. tropicalis, C. maltosa, C.
apicola, C.
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paratropicalis, C. alb/cans, C. cloacae, C. guillermondii, C. intermedia, C.
lipolytica, C.
panapsilosis and C. zeylenoides. In some embodiments, the yeast is Candida
tropical/s. In
some embodiments, the yeast is a non-oleaginous yeast. In some embodiments,
the non-
oleaginous yeast is a Saccharomyces species. In some embodiments, the
Saccharomyces
species is Saccharomyces cerevisiae . In some embodiments, the yeast is an
oleaginous yeast.
In some embodiments, the oleaginous yeast is a Rhodosporidium species. In some
embodiments, the Rhodosporidium species is Rhodosporidium toruloides.
[0080] In some embodiments the microbe is a bacterium. Bacterial host cells
suitable for the
invention include, but are not limited to, Escherichia, Corynebacterium,
Pseudomonas,
Streptomyces, and Bacillus. In some embodiments, the Escherichia cell is an E.
coli, E.
albertii, E. fergusonii, E. hermanii, E. marmotae, or E. vulneris. In some
embodiments, the
Corynebacterium cell is Corynebacterium glutamicum, Corynebacterium
kroppenstedtii,
Corynebacterium alimapuense, Corynebacterium amycolatum, Corynebacterium
diphtheriae,
Corynebacterium efficiens, Corynebacterium jeikeium, Corynebacterium
macginleyi,
Corynebacterium matruchotii, Corynebacterium minutissimum, Corynebacterium
renale,
Corynebacterium striatum, Corynebacterium ukerans, Corynebacterium
urealyticum, or
Corynebacterium uropygiale. In some embodiments, the Pseudomonas cell is a P.
putida, P.
aeruginosa, P. chlororaphis, P. fluor escens , P. pertucinogena, P. stutzeri,
P. syringae, P.
cremoricolorata, P. entomophila, P. fulva, P. monteilii, P. mosselii, P.
oryzihabitans, P.
parafluva, or P. plecoglossicida. In some embodiments, the Streptomyces cell
is a S.
coelicolor, S. lividans, S. venezuelae, S. ambofaciens, S. avermitilis, S.
albus, or S. scab/es. In
some embodiments, the Bacillus cell is a B. subtilis, B. megaterium, B.
licheniformis, B.
anthracis, B. amyloliquefaciens, or B. pumilus.
BIOFUEL
[0081] In some embodiments, the biofuel produced is ethanol, or any other
organic molecule,
described produced in a cell taught in U.S. Patent Nos. 7,985,567; 8,420,833;
8,852,902;
9,109,175; 9,200,298; 9,334,514; 9,376,691; 9,382,553; 9,631,210; 9,951,345;
and
10,167,488; and PCT International Patent Application Nos. PCT/US14/48293,
PCT/US2018/049609, PCT/US2017/036168, PCT/US2018/029668, PCT/US2008/068833,
PCT/US2008/068756, PCT/US2008/068831, PCT/US2009/042132, PCT/US2010/033299,
PCT/US2011/053787, PCT/US2011/058660, PCT/US2011/059784, PCT/US2011/061900,
PCT/US2012/031025, and PCT/U52013/074214 (all of which are incorporated in
their
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entireties by reference).
BIOMASS
[0082] The biomass can be obtained from one or more feedstock, such as
softwood
feedstock, hardwood feedstock, grass feedstock, and/or agricultural feedstock,
or a mixture
thereof.
[0083] Softwood feedstocks include, but are not limited to, Araucaria (e.g. A.
cunninghamii,
A. angustifolia, A. araucana); softwood Cedar (e.g. Juniperus virginiana, Thuj
a plicata, Thuj a
occidentalis, Chamaecyparis thyoides Callitropsis nootkatensis); Cypress (e.g.
Chamaecyparis, Cupressus Taxodium, Cupressus arizonica, Taxodium distichum,
Chamaecyparis obtusa, Chamaecyparis lawsoniana, Cupressus semperviren); Rocky
Mountain Douglas fir; European Yew; Fir (e.g. Abies balsamea, Abies alba,
Abies procera,
Abies amabilis); Hemlock (e.g. Tsuga canadensis, Tsuga mertensiana, Tsuga
heterophylla);
Kauri; Kaya; Larch (e.g. Larix decidua, Larix kaempferi, Larix laricina, Larix
occidentalis);
Pine (e.g. Pinus nigra, Pinus banksiana, Pinus contorta, Pinus radiata, Pinus
ponderosa, Pinus
resinosa, Pinus sylvestris, Pinus strobus, Pinus monticola, Pinus lambertiana,
Pinus taeda,
Pinus palustris, Pinus rigida, Pinus echinata); Redwood; Rimu; Spruce (e.g.
Picea abies,
Picea mariana, Picea rubens, Picea sitchensis, Picea glauca); Sugi; and
combinations/hybrids
thereof.
[0084] For example, softwood feedstocks which may be used herein include
cedar; fir; pine;
spruce; and combinations thereof The softwood feedstocks for the present
invention may be
selected from loblolly pine (Pinus taeda), radiata pine, jack pine, spruce
(e.g., white, interior,
black), Douglas fir, Pinus silvestris, Picea abies, and combinations/hybrids
thereof The
softwood feedstocks for the present invention may be selected from pine (e.g.
Pinus radiata,
Pinus taeda); spruce; and combinations/hybrids thereof
[0085] Hardwood feedstocks include, but are not limited to, Acacia; Afzelia;
Synsepalum
duloificum; Albizia ; Alder (e.g. Alnus glutinosa, Alnus rubra ); Applewood;
Arbutus; Ash
(e.g. F. nigra, F. quadrangulata, F. excelsior, F. pennsylvanica lanceolata,
F. latifolia, F.
profunda, F. americana ); Aspen (e.g. P. grandidentata, P. tremula, P.
tremuloides );
Australian Red Cedar ( Toona ciliata ); Ayna ( Distemonanthus benthamianus );
Balsa (
Ochroma pyramidale ); Basswood (e.g. T. americana, T. heterophylla ); Beech
(e.g. F.
sylvatica, F. grandifolia ); Birch; (e.g. Betula populifolia, B. nigra, B.
papyrifera, B. lenta, B.
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alleghaniensis/B. lutea, B. pendula, B. pubescens ); Blackbean; Blackwood;
Bocote;
Boxelder; Boxwood; Brazilwood; Bubing a; Buckeye (e.g. Aesculus hippocastanum,
Aesculus glabra, Aesculus flava/Aesculus octandra ); Butternut; Catalpa; Chemy
(e.g. Prunus
serotina, Prunus pennsylvanica, Prunus avium ); Crabwood; Chestnut; Coachwood;
Cocobolo; Corkwood; Cottonwood (e.g. Populus balsamifera, Populus deltoides,
Populus
sargentii, Populus heterophylla ); Cucumbertree; Dogwood (e.g. Cornus florida,
Cornus
nuttallii ); Ebony (e.g. Diospyros kurzii, Diospyros melanida, Diospyros
crassiflora ); Elm
(e.g. Ulmus americana, Ulmus procera, Ulmus thomasii, Ulmus rubra, Ulmus
glabra);
Eucalyptus; Greenheart; Grenadilla; Gum (e.g. Nyssa sylvatica, Eucalyptus
globulus,
Liquidambar styraciflua, Nyssa aquatica ); Hickory (e.g. Carya alba, Carya
glabra, Carya
ovata, Carya laciniosa ); Hornbeam; Hophornbeam; Ipe; Iroko; Ironwood (e.g.
Bangkirai,
Carpinus caroliniana, Casuarina equisetifolia, Choricbangarpia subargentea,
Copaifera spp.,
Eusideroxylon zwageri, Guajacum officinale, Guajacum sanctum, Hopea odorata,
Ipe,
Krugiodendronferreum, Lyonothamnus lyonii ( L. floribundus ), Mesua ferrea,
Olea spp.,
Olneya tesota, Ostrya virginiana, Parrotia persica, Tabebuia serratifolia );
Jacaranda; Jotoba;
Lacewood; Laurel; Limba; Lignum vitae; Locust (e.g. Robinia pseudacacia,
Gleditsia
triacanthos ); Mahogany; Maple (e.g. Acer saccharum, Acer nigrum, Acer
negundo, Acer
rubrum, Acer saccharinum, Acer pseudoplatanus ); Meranti; Mpingo; Oak (e.g.
Quercus
macrocarpa, Quercus alba, Quercus stellata, Quercus bicolor, Quercus
virginiana, Quercus
michauxii, Quercus prinus, Quercus muhlenbergii, Quercus chrysolepis, Quercus
lyrata,
Quercus robur, Quercus petraea, Quercus rubra, Quercus velutina, Quercus
laurifolia,
Quercus falcata, Quercus nigra, Quercus phellos, Quercus texana ); Obeche;
Okoume;
Oregon Myrtle; California Bay Laurel; Pear; Poplar (e.g. P. balsamifera, P.
nigra, Hybrid
Poplar ( Populusxcanadensis )); Ramin; Red cedar; Rosewood; Sal; Sandalwood;
Sassafras;
Satinwood; Silky Oak; Silver Wattle; Snakewood; Sourwood; Spanish cedar;
American
sycamore; Teak; Walnut (e.g. Juglans nigra, Juglans regia); Willow (e.g. Salix
nigra, Salix
alba); Yellow poplar ( Liriodendron tulipifera ); Bamboo; Palmwood; and
combinations/hybrids thereof.
[0086] For example, hardwood feedstocks for the present invention may be
selected from
Acacia, Aspen, Beech, Eucalyptus, Maple, Birch, Gum, Oak, Poplar, and
combinations/hybrids thereof. The hardwood feedstocks for the present
invention may be
selected from Populus spp. (e.g. Populus tremuloides), Eucalyptus spp. (e.g.
Eucalyptus
globulus), Acacia spp. (e.g. Acacia dealbata), and combinations thereof
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[0087] Grass feedstocks include, but are not limited to, C4 or C3 grasses,
e.g. Switchgrass,
Indiangrass, Big Bluestem, Little Bluestem, Canada Wildrye, Virginia Wildrye,
and
Goldenrod wildflowers, etc, amongst other species known in the art.
[0088] Agricultural feedstocks include, but are not limited to, agricultural
byproducts such as
husks, stovers, foliage, and the like. Such agricultural byproducts can be
derived from crops
for human consumption, animal consumption, or other non-consumption purposes.
Such
crops can be corps such as corn, wheat, sorghum, rice, soybeans, hay,
potatoes, cotton, or
sugarcane. The feedstock can arise from the harvesting of crops from the
following practices:
intercropping, mixed intercropping, row cropping, relay cropping, and the
like.
[0089] In some embodiments, the biomass is an ensiled biomass. In some
embodiment, the
biomass is ensiled by placing the biomass in an enclosed container or room,
such as a silo, or
by piling it in a heap covered by an airproof layer, such as a plastic film.
The biomass
undergoing the ensiling, known as the silage, goes through a bacterial
fermentation process
resulting in production of volatile fatty acids. In some embodiment, the
ensiling comprises
adding ensiling agents such as sugars, lactic acid or inculants. In some
embodiments, the
ensiled biomass comprises one or more toxic compounds. In some embodiments,
when
ensiled biomass comprises one or more toxic compounds, the microbe is
resistant to the one
or more toxic compounds.
Example 1
Distillable Ionic Liquids/Deep Eutectic Solvents for an Effective Recycling
and
Recovery Approach
[0090] Pretreatment using ionic liquids (ILs) is one of the most effective
methods for
producing high yields of lignin and biomass-derived fermentable sugars,
however, there are
few economical methods for IL recovery/recycling. This reality has hitherto
limited the
commercial potential of this process; therefore, it is crucial to develop
recyclable ILs as green
solvents for biomass pretreatment. Our current research focuses on developing
recyclable IL
pretreatment technologies while simultaneously facilitating the efficient
depolymerization of
both polysaccharides and lignin. This process is primarily enabled by
utilizing a recycling
method (based on distillation) that can be readily integrated with the
pretreatment process for
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a one-pot/consolidated approach.
[0091] Developing a low-cost and high efficiency lignocellulosic biomass
deconstruction
process is a critical step towards the widespread adoption of lignocellulosic
biofuels. Ionic
liquids (ILs) and deep eutectic solvents (DESs) are novel alternative solvents
for biomass
pretreatment and conversion, and they are most notably one of the most
effective methods for
producing lignin and high yields of fermentable sugars for bioenergy
production. Despite
their commercial potential, the cost of IL/DES utilization (typically
associated with their
synthesis, purification and reuse/recycling) is a significant problem that
must be addressed
before an affordable IL/DES-based process is commercially viable. Therefore,
this study
features the use of distillable solvents for the development of an integrated
biomass
pretreatment approach that combines effective pretreatment with a simplistic
and energy
efficient recovery/recycling method.
[0092] Protic ionic liquids (PILs) that are formed with the combination of
organic
ammonium-based cations and organic carboxylic acid-based anions are an
attractive group of
solvents worth considering for this process. PILs are acid-base conjugate ILs
that can be
synthesized via the direct addition of their acid and base precursors.
Additionally, when
sufficient energy is employed, they can dissociate back into their neutral
acid and base
precursors, while the PILs are re-formed upon cooling. This presents a
suitable way to
recover and recycle the ILs after their application.
[0093] The Pit - hydroxyethylammonium acetate - [Eth][0Ac] - has already been
demonstrated as an effective solvent for biomass pretreatment and is also
relatively cheap due
to its ease of synthesis.' Therefore, this Pit and chemically analogous PILs
were studied for
their distillability, as well as, their effect on biomass deconstruction in a
one-pot/consolidated
process. Preliminary results indicate a Pit recovery of 98% for "neat" IL
distillation of
[Eth][0Ac]), followed by Pit recovery [-80-85%] after biomass pretreatment
with 15%
biomass loading. Following the Pit removal, the residual biomass was
saccharified to
generate ¨74% total sugars (compared to ¨78% sugars for - One pot and ¨91%
sugars- Early
separation).
[0094] This is a promising proof of concept that supports our approach for
distilling ionic
liquids as a recovery method. Once optimized, this will launch our research
into economic
regimes, making an IL-based biorefinery a realizable goal.
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[0095] Sun, J.; Konda, N. V. S. N. M.; Parthasarathi, R.; Dutta, T.; Valiev,
M.; Xu, F.;
Simmons, B. A.; Singh, S. One-Pot Integrated Biofuel Production Using Low-Cost
Biocompatible Protic Ionic Liquids. Green Chem. 2017, 19(13), 3152-3163.
Example 2
Distillable Ionic Liquids/Deep Eutectic Solvents for an Effective Recycling
and
Recovery Approach
[0096] Distillation efficiency is measured using the following procedure:
pretreat at 100 C
for 1 hour; distill at 100 C for 1 hours in full vacuum, 40% solid loading
(SL) with
ethanolamine, enzyme saccharification (5%, 10%, 20% SL), and 10 mg/g biomass
of
CTEC/HTEC 9/1 cellulase. Distillation efficiency can be measured by
determining the
concentration of pretreating solvent in the solids after pretreatment. Figure
4 shows the
removal of the solvent by distillation is about 98.7%. Figure 5 shows the
analysis of sugars
and acids in solids after distillation. Figure 6 shows the analysis of
aromatics in solids after
distillation.
[0097] Figure 7 shows the sugar release after pretreatment, distillation and
saccharification in
a variety of percentages of solid loading. The procedure comprises: Opretreat
at 100 C for 1
hour; distill at 100 C for 1 hours in full vacuum, 40% SL with ethanolamine,
enzyme
saccharification (5%, 10%, 20% SL), and 10 mg/g biomass of CTEC/HTEC 9/1
cellulase.
[0098] It is to be understood that, while the invention has been described in
conjunction with
the preferred specific embodiments thereof, the foregoing description is
intended to illustrate
and not limit the scope of the invention. Other aspects, advantages, and
modifications within
the scope of the invention will be apparent to those skilled in the art to
which the invention
pertains.
[0099] All patents, patent applications, and publications mentioned herein are
hereby
incorporated by reference in their entireties.
[00100] While
the present invention has been described with reference to the specific
embodiments thereof, it should be understood by those skilled in the art that
various changes
may be made and equivalents may be substituted without departing from the true
spirit and
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CA 03172048 2022-08-17
WO 2021/168154 PCT/US2021/018630
scope of the invention. In addition, many modifications may be made to adapt a
particular
situation, material, composition of matter, process, process step or steps, to
the objective,
spirit and scope of the present invention. All such modifications are intended
to be within the
scope of the claims appended hereto.
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